The BSU (Battery Support Unit) is necessary for providing the required energy when the key is on and the engine is off (KOEO), especially during diagnostic phases, ADAS work or vehicle demonstrations in a showroom. DIAGNOSTIC - Compensates for energy requirements up to 100Amp. Adjustable voltage from 12v to 14.8v in steps of 0.1v according to the vehicle manufacturers specifications. Suitable for 12v batteries from 10-1200ah. CHARGES 9 step charging curve for all lead acid batteries including AGM/EFB Stop Start, SOS recovery of sulphated battery. SHOWROOM maintains the charge of a vehicles battery while in a showroom, key on, engine off. Made in France.